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Researchers Put 'Spin' in Silicon 50

Posted by CowboyNeal from the while-the-dj-revolves-it dept.
ccellist writes "Physorg.com is reporting on the University of Delaware and Cambridge NanoTech's experiments regarding 'spintronics,' or the ability to use information about electron spin in atoms of silicon to encode information, much like we use information about an electron's charge state in computers today. 'Spintronics' research hopes to usher in a new age of computer speed and performance by measuring and even controlling the angular momentum displayed by all electrons, and using this information to encode data. Researchers for the first time have successfully conducted the spin of electrons in a custom-made silicon chip, a process known as 'spin transport.'"
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Researchers Put 'Spin' in Silicon More

Researchers Put 'Spin' in Silicon

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  • I'd like to see the Luddites try putting a spin on this one.

    • It's actually quite straightforward. (Score:3, Informative)

      by Anonymous Coward
      This sort of physics is actually pretty easy to comprehend, so I'm not sure how it could be twisted.

      Basically, we can think of an atom as a sea urchin. So around this atom, we have a number of spikes. These can be considered the electrons of the atom. Now, this is a major simplification of Schroedinger's equation, but essentially each spike represents the probabilty of locating an electron within a volume of space.

      Now, these spikes come in pairs, in order to balance each other. They're on opposite sides of

      • Re: (Score:1)

        by Nullav ( 1053766 )
        I'm a bit confused by your analogy. I was convinced that electrons didn't orbit in any sort of path, and that they just constantly moved to random positions in the shell.

        • Re: (Score:3, Insightful)

          by Anonymous Coward
          You're actually thinking of the outdated Rutherford-Moore model of the atom. While it was practical back in its day, it doesn't adequately describe much of the observed phenomena since that time. That's why we need to look towards models like those of quantum mechanics, where we're not dealing with randomness (because we're not in actuality), and instead we're dealing with probability distributions.

          Think of the sea urchin spikes as the probability density function of a three-dimensional Bell curve. We have
          • Thanks for that - very helpful.

            Things like this are why I still come to Slashdot.
          • Posting just to agree with the sibling. Thanks, both of you. Visual descriptions like that are a fantastic aid to get a starting grasp of what in the world the theory is talking about.

            I've run across mentions of the Pauli exclusion principle before, but with this 'model' in hand I'll take another look at it.
        • quantum mechanics is very zen. as described in the model, you can't really think of electrons (or particles in general) as having position -- they don't. they have probabilities of being somewhere. ...and then you take the fourier transform of it and demonstrate the uncertainty principle, it's really cool. kind of trippy actually.

          i'm a college student who took an introductory class on quantum computing with a really cool professor.
    • Keep Bill O'Reilly [billoreilly.com] away from these guys!
  • spin control was fully in the political domain? Does this mean that politicians will soon begin to understand the Intarweb tubes?

  • Angular momentum (Score:5, Funny)

    by suv4x4 ( 956391 ) on Saturday May 19, 2007 @11:00AM (#19191031)
    Quoting from a movie I saw once. The editor tells the article author how he edited his work:

    Editor: "I replaced atom with molecule here and there, atom repeats too much"
    Author: "But... it's not the same thing at all!"
    Editor: "Oh come on! Who'll know the difference. Molecule, atom.. same thing to me."

    So, in the light of this, particle "spin" isn't about an electron actually spinning, and thus "angular momentum" as seen in the article text, so that's pretty hilarious replacement.

    Another thing you may want to know for future articles: quark colors also aren't actual colors.

    • Re: (Score:3, Funny)

      by Hemogoblin ( 982564 )

      It was here that the thaum, hitherto believed to be the smallest possible particle of magic, was succesfully demonstrated to be made up of /resons/ (Lit.: 'Thing-ies') or reality fragments. Currently research indicates that each reson is itself made up of a combination of at least five 'flavours', known as 'up', 'down', 'sideways', 'sex appeal' and 'peppermint'.

      - Terry Pratchett, Lords and Ladies

    • Re: (Score:3, Informative)

      by chrisb33 ( 964639 )
      Unfortunately, the "hilarious" joke is on you, since spin actually does refer to angular momentum. It can even be interchanged with "orbital" (extrinsic) angular momentum while obeying momentum conservation, and (as the article mentions) can be measured using a magnetic field.

      A quick look at wikipedia [wikipedia.org] before posting is usually helpful.

      • Re: (Score:2)

        by suv4x4 ( 956391 )
        Unfortunately, the "hilarious" joke is on you, since spin actually does refer to angular momentum.

        Well, I admit defeat, but at least now we all collectively have something to laugh about.
      • If my laptop has a spin-based CPU and I flip it upside down do all the white pixels turn black and vice versa?

        This is completely not an issue with a charge-based CPU.

    • Re: (Score:2, Funny)

      by noidentity ( 188756 )
      'So, in the light of this, particle "spin" isn't about an electron actually spinning, and thus "angular momentum" as seen in the article text, so that's pretty hilarious replacement.'

      I offer "angular momentum enhancement" as a politically-correct alternative to "spin control".

  • Expanding markets (Score:3, Funny)

    by HotBBQ ( 714130 ) on Saturday May 19, 2007 @12:07PM (#19191469)
    I have a far more entertaining idea for spinning silicone. It mostly involves cheesy stage names and tassels.

  • Sounds like MRI (Score:4, Interesting)

    by necro81 ( 917438 ) on Saturday May 19, 2007 @12:23PM (#19191591) Journal

    After spin injection, electrons in the silicon were then subjected to a magnetic field, which caused their spin direction to "precess" or gyrate (much like gravity's effect on a rotating gyroscope), producing tell-tale oscillations in their measurement.

    This sounds like the process used in Magnetic Resonance Imaging [wikipedia.org]. In MRI, they use a BIG magnet to create a very strong magnetic field in a person's body. The main field is usually 1-3 Tesla, depending on the scanner (for reference, Earth's magnetic field is 30-50 microtesla). Then they use smaller magnets to establish a gradient in that main field, and RF pulses to query the spin precession of atoms in the body. In the case of human imaging, I think they focus on the spin precession of a hydrogen nucleus (a proton) in water. In function MRI, they focus on hemoglobin (which contains a little ferromagnetic iron, ya see), to determine where blood is most present. See this [rit.edu] for an exhaustive overview of how it works.

    Their spintronics methods sound similar, except it's focused on a much smaller volume (a chip instead of a human body), and are tuned to the electrons in doped silicon. Very cool.

    • which contains a little ferromagnetic iron, ya see
      AFAIK, iron in hemoglobin isn't ferromagnetic
      • The hemoglobin molecule in humans and related life forms, uses one individual iron atom. Four of these proteins are used in each red blood cell. The iron atoms are held by the carbon chains in the proteins at distances that put them much farther apart than they would be in an iron crystal, and not directly bonded to each other, so there are no crystal domains that can be lined up by a magnetic field.
        To put it another way, normally, what scientists mean by 'ferromagnetic' is both that the doma
    • MRI has nothing to do with blood per se (PET is what you use to image activity).
      It's just the medical/consumer friendly term for NMR (nuclear magnetic resonance).
      It also has nothing to do with electromagnetism (e.g; ferromentism), but instead on
      the magnet moment resulting from unpaired nucleons that occur in some isotopes of
      various elements e.g; 1H and 13C.
  • "much like we use information about an electron's charge state in computers today"

    Obviously the charge of an electron is constant (in case you get confused eV is a measurement of velocity, not charge). What we use in computers today is the QUANTITY of electrons "flowing" (these days tunnelling may be a better term) through non-conductive layers.

    And no non-conductive is exactly where it needs to be. The edge of today's transistor is a non-conductive, but very small, silicon edge.

    • Re:Big mistake in the summary (Score:4, Informative)

      by l2718 ( 514756 ) on Saturday May 19, 2007 @01:44PM (#19192237)

      Obviously the charge of an electron is constant (in case you get confused eV is a measurement of velocity, not charge). What we use in computers today is the QUANTITY of electrons "flowing" (these days tunnelling may be a better term) through non-conductive layers.

      Man, there are so many errors here I don't know where to begin. The Electron-Volt (eV) is a unit of energy (the work required to move an electron across a potential different of one Volt). Digital computers do not depend on the magnitude of the current, but on its abssence or presence. In fact, the goal is to have as little current as possible (less losses due to heat and radiation) -- we are nearing single-electron transistors. "Spintronics" would instead carry the information in the spin state (up or down) of an electron. The reference to "charge" probably stems from memory, where information is stored in the magnetization state of a small amount of matter.

      • Re: (Score:2)

        by glwtta ( 532858 )
        Regardless, this: "we use information about an electron's charge state in computers today" is still a ridiculous statement.

      • Digital computers do not depend on the magnitude of the current, but on its abssence or presence.

        What you have just described is in fact a measure of magnitude of current, where a current above a certain threshold produces an output voltage high enough to be considered a 1, and a current below another threshold produces an output voltage corresponding to a 0. This is how early digital electronics worked.

        But in modern CMOS digital circuits, 1's and 0's are represented by voltage levels, not current ma

      • Man, there are so many errors here I don't know where to begin. The Electron-Volt (eV) is a unit of energy (the work required to move an electron across a potential different of one Volt). Digital computers do not depend on the magnitude of the current, but on its abssence or presence. In fact, the goal is to have as little current as possible (less losses due to heat and radiation) -- we are nearing single-electron transistors. "Spintronics" would instead carry the information in the spin state (up or down

    • As the other poster said, eV is a unit of energy, not velocity. Velocity is in ms^-1. 1ev ~ 1.6e-19 joules.

      Obviously the charge of an electron is constant (in case you get confused eV is a measurement of velocity, not charge). What we use in computers today is the QUANTITY of electrons "flowing" (these days tunnelling may be a better term) through non-conductive layers.

      What the article means is that we use the charge of an electron to transmit information at this point, rather than the spin or other pr

    • Thanks for clearing that up for me. I guess I misunderstand the way the 1's and 0's look like at the atomic level. So you're saying that below a certain threshold of electrons flowing the IC yields a zero ("false"), and above that a 1 ("true")?
  • is a stupid name. It sounds like a fad exercise routine.
  • John C. Dvorak when you need him?

    http://en.wikipedia.org/wiki/Silicon_Spin [wikipedia.org]
    • Gah, someone actually beat me to it!

      "Silicon Spin" was probably the last good thing Dvorak did before he went all psycho on the tech industry.

      (Of course, considering the TV abomination that is now "G4", I'd probably go a little psycho too...)
  • FTFA:

    "We hope we're with spintronics where Bell Labs was with semiconductor electronics in 1948," Appelbaum said.
    Does that mean we're about 30 years away from being able to buy something "cool" based on this?
  • Is there an energy difference between the two spin states, in joules (or electron-volts, whatever the unit), the way there's an energy difference between an atom with an electron in two different orbit shell states?

    If so, how much is the difference? Is there a way to move an electron from the higher energy spin state to the lower one that consumes less energy than the state difference? A way to move the electron from lower energy to higher energy spin state that is less than the difference? Can those moves
    • This is way outside my field, but I can give it a shot. From what I understand spin isn't a question of energy state, rather it's a property of electrons, like magnetism is for some metals (this is probably a terribly innacurate comparison, so any physicists out there cut me some slack). An electron can either have up spin or down spin, so you have the capability to represent a bit with the spin state of a electron. Now, what makes spintronics looks so good is two properties. One, because you aren't shoving
      • Yes to all that, but I believe the two different spin states have different energy levels - even if the subatomic mechanics are currently unknown. And that it takes energy, however small, to change the states - but that one "direction" of change requires more, and that perhaps the other direction returns at least some of that energy.

        There is a mechanical change, some "stuff" is in a different physical location, when changing electron spin. The two states might have the same energy level, changing between th
  • Okay, call it offtopic, whatever. But I reckon Teh Cowboy has been waiting for a decade to post an article with ANY Vanilla Ice reference possible.

    ALL HAIL TEH NEILZORZ!!!!!

    Okay, now I'm going to be in negative karma for this, but it's worth it.

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